drivers/mtd/nand/raw/ingenic/jz4780_bch.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * JZ4780 BCH controller driver
   4  *
   5  * Copyright (c) 2015 Imagination Technologies
   6  * Author: Alex Smith <alex.smith@imgtec.com>
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/clk.h>
  11 #include <linux/device.h>
  12 #include <linux/io.h>
  13 #include <linux/iopoll.h>
  14 #include <linux/module.h>
  15 #include <linux/mutex.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/platform_device.h>
  18
  19 #include "ingenic_ecc.h"
  20
  21 #define BCH_BHCR                        0x0
  22 #define BCH_BHCCR                       0x8
  23 #define BCH_BHCNT                       0xc
  24 #define BCH_BHDR                        0x10
  25 #define BCH_BHPAR0                      0x14
  26 #define BCH_BHERR0                      0x84
  27 #define BCH_BHINT                       0x184
  28 #define BCH_BHINTES                     0x188
  29 #define BCH_BHINTEC                     0x18c
  30 #define BCH_BHINTE                      0x190
  31
  32 #define BCH_BHCR_BSEL_SHIFT             4
  33 #define BCH_BHCR_BSEL_MASK              (0x7f << BCH_BHCR_BSEL_SHIFT)
  34 #define BCH_BHCR_ENCE                   BIT(2)
  35 #define BCH_BHCR_INIT                   BIT(1)
  36 #define BCH_BHCR_BCHE                   BIT(0)
  37
  38 #define BCH_BHCNT_PARITYSIZE_SHIFT      16
  39 #define BCH_BHCNT_PARITYSIZE_MASK       (0x7f << BCH_BHCNT_PARITYSIZE_SHIFT)
  40 #define BCH_BHCNT_BLOCKSIZE_SHIFT       0
  41 #define BCH_BHCNT_BLOCKSIZE_MASK        (0x7ff << BCH_BHCNT_BLOCKSIZE_SHIFT)
  42
  43 #define BCH_BHERR_MASK_SHIFT            16
  44 #define BCH_BHERR_MASK_MASK             (0xffff << BCH_BHERR_MASK_SHIFT)
  45 #define BCH_BHERR_INDEX_SHIFT           0
  46 #define BCH_BHERR_INDEX_MASK            (0x7ff << BCH_BHERR_INDEX_SHIFT)
  47
  48 #define BCH_BHINT_ERRC_SHIFT            24
  49 #define BCH_BHINT_ERRC_MASK             (0x7f << BCH_BHINT_ERRC_SHIFT)
  50 #define BCH_BHINT_TERRC_SHIFT           16
  51 #define BCH_BHINT_TERRC_MASK            (0x7f << BCH_BHINT_TERRC_SHIFT)
  52 #define BCH_BHINT_DECF                  BIT(3)
  53 #define BCH_BHINT_ENCF                  BIT(2)
  54 #define BCH_BHINT_UNCOR                 BIT(1)
  55 #define BCH_BHINT_ERR                   BIT(0)
  56
  57 #define BCH_CLK_RATE                    (200 * 1000 * 1000)
  58
  59 /* Timeout for BCH calculation/correction. */
  60 #define BCH_TIMEOUT_US                  100000
  61
  62 static void jz4780_bch_reset(struct ingenic_ecc *bch,
  63                              struct ingenic_ecc_params *params, bool encode)
  64 {
  65         u32 reg;
  66
  67         /* Clear interrupt status. */
  68         writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
  69
  70         /* Set up BCH count register. */
  71         reg = params->size << BCH_BHCNT_BLOCKSIZE_SHIFT;
  72         reg |= params->bytes << BCH_BHCNT_PARITYSIZE_SHIFT;
  73         writel(reg, bch->base + BCH_BHCNT);
  74
  75         /* Initialise and enable BCH. */
  76         reg = BCH_BHCR_BCHE | BCH_BHCR_INIT;
  77         reg |= params->strength << BCH_BHCR_BSEL_SHIFT;
  78         if (encode)
  79                 reg |= BCH_BHCR_ENCE;
  80         writel(reg, bch->base + BCH_BHCR);
  81 }
  82
  83 static void jz4780_bch_disable(struct ingenic_ecc *bch)
  84 {
  85         writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
  86         writel(BCH_BHCR_BCHE, bch->base + BCH_BHCCR);
  87 }
  88
  89 static void jz4780_bch_write_data(struct ingenic_ecc *bch, const void *buf,
  90                                   size_t size)
  91 {
  92         size_t size32 = size / sizeof(u32);
  93         size_t size8 = size % sizeof(u32);
  94         const u32 *src32;
  95         const u8 *src8;
  96
  97         src32 = (const u32 *)buf;
  98         while (size32--)
  99                 writel(*src32++, bch->base + BCH_BHDR);
 100
 101         src8 = (const u8 *)src32;
 102         while (size8--)
 103                 writeb(*src8++, bch->base + BCH_BHDR);
 104 }
 105
 106 static void jz4780_bch_read_parity(struct ingenic_ecc *bch, void *buf,
 107                                    size_t size)
 108 {
 109         size_t size32 = size / sizeof(u32);
 110         size_t size8 = size % sizeof(u32);
 111         u32 *dest32;
 112         u8 *dest8;
 113         u32 val, offset = 0;
 114
 115         dest32 = (u32 *)buf;
 116         while (size32--) {
 117                 *dest32++ = readl(bch->base + BCH_BHPAR0 + offset);
 118                 offset += sizeof(u32);
 119         }
 120
 121         dest8 = (u8 *)dest32;
 122         val = readl(bch->base + BCH_BHPAR0 + offset);
 123         switch (size8) {
 124         case 3:
 125                 dest8[2] = (val >> 16) & 0xff;
 126                 fallthrough;
 127         case 2:
 128                 dest8[1] = (val >> 8) & 0xff;
 129                 fallthrough;
 130         case 1:
 131                 dest8[0] = val & 0xff;
 132                 break;
 133         }
 134 }
 135
 136 static bool jz4780_bch_wait_complete(struct ingenic_ecc *bch, unsigned int irq,
 137                                      u32 *status)
 138 {
 139         u32 reg;
 140         int ret;
 141
 142         /*
 143          * While we could use interrupts here and sleep until the operation
 144          * completes, the controller works fairly quickly (usually a few
 145          * microseconds) and so the overhead of sleeping until we get an
 146          * interrupt quite noticeably decreases performance.
 147          */
 148         ret = readl_poll_timeout(bch->base + BCH_BHINT, reg,
 149                                  (reg & irq) == irq, 0, BCH_TIMEOUT_US);
 150         if (ret)
 151                 return false;
 152
 153         if (status)
 154                 *status = reg;
 155
 156         writel(reg, bch->base + BCH_BHINT);
 157         return true;
 158 }
 159
 160 static int jz4780_calculate(struct ingenic_ecc *bch,
 161                             struct ingenic_ecc_params *params,
 162                             const u8 *buf, u8 *ecc_code)
 163 {
 164         int ret = 0;
 165
 166         mutex_lock(&bch->lock);
 167
 168         jz4780_bch_reset(bch, params, true);
 169         jz4780_bch_write_data(bch, buf, params->size);
 170
 171         if (jz4780_bch_wait_complete(bch, BCH_BHINT_ENCF, NULL)) {
 172                 jz4780_bch_read_parity(bch, ecc_code, params->bytes);
 173         } else {
 174                 dev_err(bch->dev, "timed out while calculating ECC\n");
 175                 ret = -ETIMEDOUT;
 176         }
 177
 178         jz4780_bch_disable(bch);
 179         mutex_unlock(&bch->lock);
 180         return ret;
 181 }
 182
 183 static int jz4780_correct(struct ingenic_ecc *bch,
 184                           struct ingenic_ecc_params *params,
 185                           u8 *buf, u8 *ecc_code)
 186 {
 187         u32 reg, mask, index;
 188         int i, ret, count;
 189
 190         mutex_lock(&bch->lock);
 191
 192         jz4780_bch_reset(bch, params, false);
 193         jz4780_bch_write_data(bch, buf, params->size);
 194         jz4780_bch_write_data(bch, ecc_code, params->bytes);
 195
 196         if (!jz4780_bch_wait_complete(bch, BCH_BHINT_DECF, &reg)) {
 197                 dev_err(bch->dev, "timed out while correcting data\n");
 198                 ret = -ETIMEDOUT;
 199                 goto out;
 200         }
 201
 202         if (reg & BCH_BHINT_UNCOR) {
 203                 dev_warn(bch->dev, "uncorrectable ECC error\n");
 204                 ret = -EBADMSG;
 205                 goto out;
 206         }
 207
 208         /* Correct any detected errors. */
 209         if (reg & BCH_BHINT_ERR) {
 210                 count = (reg & BCH_BHINT_ERRC_MASK) >> BCH_BHINT_ERRC_SHIFT;
 211                 ret = (reg & BCH_BHINT_TERRC_MASK) >> BCH_BHINT_TERRC_SHIFT;
 212
 213                 for (i = 0; i < count; i++) {
 214                         reg = readl(bch->base + BCH_BHERR0 + (i * 4));
 215                         mask = (reg & BCH_BHERR_MASK_MASK) >>
 216                                                 BCH_BHERR_MASK_SHIFT;
 217                         index = (reg & BCH_BHERR_INDEX_MASK) >>
 218                                                 BCH_BHERR_INDEX_SHIFT;
 219                         buf[(index * 2) + 0] ^= mask;
 220                         buf[(index * 2) + 1] ^= mask >> 8;
 221                 }
 222         } else {
 223                 ret = 0;
 224         }
 225
 226 out:
 227         jz4780_bch_disable(bch);
 228         mutex_unlock(&bch->lock);
 229         return ret;
 230 }
 231
 232 static int jz4780_bch_probe(struct platform_device *pdev)
 233 {
 234         struct ingenic_ecc *bch;
 235         int ret;
 236
 237         ret = ingenic_ecc_probe(pdev);
 238         if (ret)
 239                 return ret;
 240
 241         bch = platform_get_drvdata(pdev);
 242         clk_set_rate(bch->clk, BCH_CLK_RATE);
 243
 244         return 0;
 245 }
 246
 247 static const struct ingenic_ecc_ops jz4780_bch_ops = {
 248         .disable = jz4780_bch_disable,
 249         .calculate = jz4780_calculate,
 250         .correct = jz4780_correct,
 251 };
 252
 253 static const struct of_device_id jz4780_bch_dt_match[] = {
 254         { .compatible = "ingenic,jz4780-bch", .data = &jz4780_bch_ops },
 255         {},
 256 };
 257 MODULE_DEVICE_TABLE(of, jz4780_bch_dt_match);
 258
 259 static struct platform_driver jz4780_bch_driver = {
 260         .probe          = jz4780_bch_probe,
 261         .driver = {
 262                 .name   = "jz4780-bch",
 263                 .of_match_table = of_match_ptr(jz4780_bch_dt_match),
 264         },
 265 };
 266 module_platform_driver(jz4780_bch_driver);
 267
 268 MODULE_AUTHOR("Alex Smith <alex@alex-smith.me.uk>");
 269 MODULE_AUTHOR("Harvey Hunt <harveyhuntnexus@gmail.com>");
 270 MODULE_DESCRIPTION("Ingenic JZ4780 BCH error correction driver");
 271 MODULE_LICENSE("GPL v2");